Sexual transmission of HIV-1 is the major pathway by which this pathogen is spread locally, nationally, and worldwide. Until recently, therapeutic interventions appeared to briefly palliate the progession of disease. In ongoing clinical trials here at the Rockefeller University conducted by the Aaron Diamond AIDS Research Center, combination antiviral regimens have reduced viral RNA levels in plasma to levels below detection. The goal of this study is to ascertain the effects of therapy on the amount of virus in semen of HIV infected men already enrolled in one of the therapeutic trials in progress here at the Rockefeller University Hospital.